The present invention relates to a magnetron sputter apparatus and a method for forming films by using the same, and in particular to a magnetron sputter apparatus and a method for forming films by using the same, which are suitable for depositing a homogeneous film on a region having a large area such as a magnetic thin film necessary for a thin film magnetic head, etc.
In a prior art sputter apparatus for simultaneously forming films on a plurality of substrates arranged in a region having a large area the films are formed on a substrate which is located opposite the center of a target, are a plurality of substrates are arranged in coaxial circles, and in addition the target is circular, as disclosed e.g. in JP-A-56-130470. In the case where films are formed simultaneously on a plurality of substrates, it has been believed that it is preferable to arrange them in a film forming region, which is circular or rectangular, in order to obtain a good film thickness distribution, from the point of view of the symmetry. Further a magnetron sputter apparatus using a rectangular target is disclosed in JP-A-58-189372. However, substrate arrangement size of the film forming region further and size of the target erosion area are not indicated in this literature. In these examples of the prior art techniques, neither shape nor size of the erosion area, which have important influences on film forming characteristics such as the film thickness distribution in the film forming region, the ratio of the film thickness on an inclined portion to that on a flat portion (step coverage), presence of an inclined portion, etc., are known and therefore they are not described.
It is believed that it is difficult to increase the productivity and to stabilize the film quality by forming simultaneously films on a plurality of substrates by means of a magnetron sputter apparatus according to the prior art techniques described above, and such techniques are not known. In particular, no knowledge was obtained concerning the size of the film forming region, the size of the target erosion area and the film forming characteristics in a magnetron type sputter apparatus, specifically from the point of view of improving the film thickness distribution in a large area; and no magnetron sputter apparatus was provided, which was capable of depositing simultaneously a film having an excellent film thickness distribution and uniform characteristics on a plurality of substrates arranged in a large area.
Furthermore, no attention has been paid to the case where the magnetic film has an inclined portion such as in a magnetic head, and there is a problem that good step coverage can not be obtained.